A lock in general and a panic lock in particular are, as known, provided with a latch bolt and a dead bolt that can be operated with a key or by means of a handle on the inside and/or outside of the door.
A panic lock is used for an emergency exit for example, whereby in the event of an emergency or panic it must always be specifically possible to open the door from the inside by means of a handle, even without a key, while from the outside it is not possible to enter inside by means of a handle on the outside, unless the person has the key or after a specific operation or combination of operations with the handle and/or with the key on the inside.
As with a panic lock the handle on the inside and a handle on the outside must not enable the same operations, it is typical for such panic locks to be equipped with two handle followers or handles that can turn with respect one another, and of which one handle follower or handle is intended to be able to be operated from the inside of the door and the other handle follower or handle is intended to be operated from the outside of the door.
Depending on the situation, the outside handle follower can be coupled to the inside handle follower to gain access with the outside handle, for example for emergency services.
Depending on what action or actions are required or desired to couple the outside handle follower to the inside handle follower after performing a panic action or panic movement to open the door with the handle on the inside, different types of panic locks are known, each with a different function.
A distinction is made between the ‘B, D and E functions,’ wherein:                function E, whereby the handle followers are permanently coupled together, whereby a key is always required to be able to enter inside from the outside as there is no handle on the outside of the door;        function D, whereby after performing a panic action with the inside handle, the handle followers are coupled together to thus gain access to the inside, also by means of the handle on the outside of the door, without a key or by means of the key if no handle is provided on the outside;        function B, whereby, after performing a panic action with the inside handle, the handle followers are only coupled together after the latch bolt has first been pulled backwards once by means of the key, after which the door can be permanently opened along the outside with the handle until the dead bolt is again turned to the locked position.        
A disadvantage of the known panic locks is that a different lock is required for each type.
A disadvantage attached to that is that these types must also be held in stock.
Moreover it is not possible to change the type without acquiring a new panic lock.
Additionally a panic lock can be mounted on the left or right of a door, whereby in the one case one of the handle followers or handles is the inside handle follower or handle while in the other case the other handle follower or handle is the inside handle follower or handle.
Also in this case two types of panic lock are generally needed each time.
A panic lock is indeed known from EP 1.743.994 in which, by moving a screw, it is possible to convert a panic lock from a left lock into a right lock and vice versa.